Israeli intelligence believes Iran has transferred thousands of uranium-enrichment centrifuges into a heavily fortified underground complex near its Natanz nuclear facility, raising fears that Tehran is rebuilding its nuclear programme beyond the reach of inspectors and conventional air strikes.
The centrifuges were moved into tunnels inside Pickaxe Mountain, also known as Mount Kolang, after the 12-day Israel-Iran war in June 2025, according to Israeli and American officials cited by the Wall Street Journal. Israel has shared its assessment with Washington.
The facility, around 135 miles south of Tehran, is believed to lie more than 100 metres beneath rock and is protected by reinforced tunnel entrances.
Its depth could make it substantially harder to destroy than Iran’s other nuclear facilities at Natanz and Fordow.
Iran began building the complex after a 2020 explosion, which may have been sabotage, damaged a centrifuge production workshop at Natanz.
Iranian officials previously said the underground site would be used to manufacture advanced centrifuges, the machines used to enrich uranium.
Iran has not allowed the International Atomic Energy Agency access to the mountain complex, and neither the alleged transfer nor the number of centrifuges inside has been independently verified.
The reported intelligence has increased concern in Israel and the United States that Iran could conduct enrichment covertly while shielding critical equipment from future attacks.
US President Donald Trump has discussed Pickaxe Mountain as a potential target as Washington considers expanding military operations against Iran, although officials have acknowledged that striking the deeply buried site would present significant operational difficulties.
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